1. Field of the Invention
The present invention related to a vacuum locking system for panels to be worked.
2. Description of Related Art
The preferential application, even if not a limitative one, concerns the manufacturing of wooden panels and the like such as hardboard, medium density etc., in the field of furniture and in particular panels for furniture, preferentially small doors, which as it is known should be moulded (shaped in their profiles) and eventually provided with mirrors (shaped inside in order to contain the known mirrors or central small mirrors).
For these types of manufacturing the panel to be worked is generally locked on a working table provided with a large plurality of holes and beneath which the vacuum is obtained in order to lock, the panel to be worked (See European Patent EP-A0505668 (issued to GPM GESELLSCHAFT Fxc3xcR FERTIGUNG UND MASCHINENBAU AGon Sep. 30, 1992) This European patent discloses a working table with vacuum aspiration for tool machines having a plurality of suction caps.
It very often occurs that, because the panels to be worked are often of different size, it is necessary to use an under-panel which has such an extension to cover all the holed planes of the working table with a series of holes on said under-panel which extend only inside of the extension surface of the overhanging panel to be worked.
This invention is obviously for avoiding that the holes beyond the panel covering range remain uncovered and that the vacuum suction effect for the panel locking is reduced.
Such a system though, requires to change always the under-panel each time that the panel to be worked needs to change dimension.
In fact there is not only the problem of allowing the functioning only of the vacuum holes concerning the surface of the panel to be worked, but also that of supplying the panel to be worked with a rising capability in order to allow a rational and complete profiling and shaping of the same panel. Therefore, when the panels are manufactured by the flanging milling machines (moulding machines), the flanging milling machine may protrude beyond the level of the lower surface of the panel to be worked.
For such reasons, the under-panel (more or less of the same material) also acts as a spacer and thus it also is etched by the tool jutting.
This fact forces the operator to change the under-panel when the type of panel to be worked changes.
The purpose of the present invention is that of obviating the above mentioned drawbacks and in particular of realizing a vacuum fixing plane for panels to be worked of any size and with no need of placing an under-panel beneath it.
The problem is solved and the purpose reached as claimed by realizing a plane equipped for the fixing on it by attraction of a panel to be worked, of the type in which said plane is provided with a plurality of suction caps with axial holes for a vacuum action, wherein:
i said suction axial holes are made within respective reciprocating pistons placed in rows along directions X and Y, which:
are provided with fluid dynamic lifting and lowering means;
during the lifting said means enable to open a suction passage in said suction axial hole and during the lowering said means enables closing it;
characterized in that:
ii said fluid dynamic lifting and lowering means consist of a series of fluid dynamic ducts which for each row in said two directions X and Y connect each reciprocating piston with the adjacent one, one series of ducts in one direction for the lifting and a second series of ducts in a second orthogonal direction for the lowering of the reciprocating pistons, and this in such a way that said involved pistons are made to work in lifting or lowering by the pressure difference of said series of ducts along direction X and Y, only in the area programmed for a corresponding panel to be worked.
Thus the immediate advantage of lifting the panel to be worked from the underlying supporting plane and simultaneously applying the vacuum suction only to the small pistons lifted beneath the panel to be worked is obtained, while the other small pistons will remain lowered, thus allowing also an easy manufacturing of the whole panel back.
Thus all the working and manufacturing technology is simplified and improved in productivity.